Method of forming cores for electrical apparatus



(No Model.)

I A. SOHMID. METHOD OF FORMING GORBS FOR ELECTRICAL APPARATUS. No. 406,859. Patented July 9, 1889.

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UNITED STATES PATENT OEEIcE.

ALBERT SOHMID, OE ALLEGHENY, ASSIGNOR TO THE WVESTINGHOUSE ELEC' TRIO COMPANY, OF PITTSBURG, PENNSYLVANIA.

METHOD OF FORMING CORES FOR ELECTRICAL APPARATUS.

SPECIFICATION forming part of Letters Patent No. 406,859, dated July 9, 1889.

Application filed May 13, 1889. Serial No. 810,600. (No model.)

To aZZ whom it may concern: formed upon the edges of the plates by the Be it known that I, ALBERT SCHMID, a citiprocess of turning the armature down are zen of the Republic of Switzerland, residing either reduced or covered with an insulating 55 in Allegheny, county of Allegheny, and State 1naterialas the oxide of the metal, for inof Pennsylvania, have invented a certain new stanceand when the plates are reassembled and useful Improvement in Methods of Formthey are separated from each other by the ing Cores for Electrical Machines, (Case No. oxide, which affords the required insulation. 320,) of which the following is a speeifica- The invention is applicable to cores of other 60 tion. apparatus than the armatures of generators My invention relates to a method of buildand motors, and in fact is applicable to any ing up or constructing the cores of electrical apparatus requiring insulated lamina}, which apparatus, and it especially relates to the ist-urned off to any given shape or size after method of building up the armature-cores of the laminae have been first assembled. 65 electric generators and motors. The invention In the accompanying drawings, Figure 1 is I 5 is, however, applicable to other apparatus, as a view of the plates of an armature-core. Fig. will be apparent from the following descrip- 2 is a side elevation of an armature-core built tion. of such plates. i

In certain forms of electric generators and Referring to the figures, A represents an 70 motors it is customary to build up the armaarmature-shaft, and B B end plates for the tures from plates, (sheets or laminze of soft armature-core. The armature may with adiron,) and to provide a more or less perfect vantage be constructed with re-enforcing insulation of the laminae. Such insulation plates Z) b applied to the plates B B In may be secured by the use of separate sheets forming the armature-core sheets or plates of 75 or plates of non-conducting substance, or it magnetizable material-such, for instance, as

.5 may be obtained by forming upon the sursoft iron, c'are placed over the shaft and faces of the laminze an oxide of the metal. piled upon the plate 13. Then a sufficient This may be accomplished by annealing the number have been applied to the shaft, they plates in such a manner as to form a more or are pressed firmly together by suitable me- 80 less non-conducting oxide over their entire chanical means, and the end plate B and a 0 surfaces. I have found that by placing to-. re-enforcing plate b are held in place in any gether plates which have been thoroughly anconvenient manner, as, for instance, by a nut nealed after they have been formed into D turning upon a screw-thread upon the arproper shape a sufficient insulation may be mature-shaft. 8 secured 5 but when the surface of an arma- In practice it is difficult to out the plates 3 5 ture thus built is turned down in order to oboriginally of such exact shape as to cause tain a smooth and true exterior, the edges of them to conform when laid together, on acthe plates are turned over or upset, so that count of the tendency to buckle, so that when the metal of contiguous plates is brought into first laid together they are of approximately 9:) contact, thus completing an electrical conne cthe proper size and shape, but usually have 40 tion throughout the surface of the core, (the slight variations in size or circumference, and portion where the tendency to establish eddytherefore it is desirable that the outer surface currents is very great,) and thus partially deof the armature be turned down, so that it feating the object of the insulation. shall be true and fit exactly and revolve 5 My present invention consists, therefore, in evenly within the field-magnet to which it is first building up an armature byplatesof the to be applied. Therefore it is placed in a proper size and shape, then turning it down suitable lathe and turned in a manner well to remove irregularities and obtain the reunderstood. By this operation, however, a quired dimensions, then taking the armature burr or overlapping edge isliable to be formed 10o apart, separating the laminze from each other, upon the surfaces of the plates, so that the then applying the insulation-ms, for instance, contiguous plates are to a greater or less exby annealing themand finally reassembling tent connected in one continuous electrical '1 them as before. In this manner the burrs circuit. After the armature has been turned off in this manner, therefore, it is taken to pieces, the plates being separated from each other. They are then coated by insulating material. This is preferablyaccomplished by placingthem in a suitable annealing-furnace and bringing them to a proper temperature to reduce the surface of the plate to a non-conducting oxide or a more or less perfectly-insulating oxide of the metal. After this process, which may be accomplished in any convenient well-known manner, the plates are reassembled and the armature is again built up and the plates bound together as before. The armature-core will now be composed of lamime separated from each other by the re quired insulation without the intervention of separate sheets or plates of insulating material.

I claim as my invention- 1. The hereinbefore-described method of constructing the laminated cores of electrical apparatus, which consists in building up the core of plates or sheets of magnetizable mate rial, turning the core to the proper shape and form, afterward separating the plates, annealing the same, and finally reassembling them.

2. As a step in the manufacture of lan1inated cores of electrical apparatus, the turning down of the core to the proper size and shape, taking down the core, annealing the laminae, and rcassembling the same.

The herein-described method of constructing the armature-core of an electric machine, which consists in mounting upon the armature-shaft laminae of magnetizable material, binding them firmly in position, with. the faces of consecutive laminze adjacent to each other in the positions which they are finally to occupy, turning down the core to the proper size and form, dissociating the laminze, annealing them, and thereby coatin their surfaces and edges with an oxide of metal, and finally rcassembling the lamime in, approximately the positions formerly occupied thereby, substantially as described.

at. The hereinbefore-described method. of constructing the laminated cores of electrical apparatus, which consists in building up the core of plates or sheets of magnetizable ma terial, turning the core to the proper shape and form, afterward separating the plates, oxidizing the same, and finally reassembling the same. 

